| 摘要 |
This invention is designed to reduce a harsh noise, by suppressing a wind noise generated at a wind-receiving end, which is caused by forming the wind-receiving end of an outlet port for air so as to be parallel to a side extending along the direction of the rotation axis of a vane of an impeller. The wind-receiving end of the outlet port is provided in the form of steps or with inclination with respect to a side extending along the direction of the rotation axis of a vane of the impeller so that the wind sent and blown out by the vanes of the impeller is prevented from blowing against the wind-receiving end all at once throughout its entire width.
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